EP 0252842 B1 19900411 - METHOD OF MAKING A TOOL FOR STAMPING ROUND SHAPED WATERMARK SCREENS USED TO MAKE FILIGRANES AND APPARATUS THEREFOR
Title (en)
METHOD OF MAKING A TOOL FOR STAMPING ROUND SHAPED WATERMARK SCREENS USED TO MAKE FILIGRANES AND APPARATUS THEREFOR
Publication
Application
Priority
FR 8610089 A 19860710
Abstract (en)
[origin: EP0252842A1] 1. Method for the production of a steel tool serving for the stamping of a forming wire of a mould used in the fiduciary paper industry for producing watermarks, said tool being obtained by electro-erosion from an electrode, comprising the following successive stages : a) the values of a black and white image are digitized (2) in pixels with several shades of grey, b) an electrode is engraved automatically by machining (6), plane by plane, directly from the preceding data, with an engraving depth increasing uniformly with respect to the initial surface of said electrode, the engraving depth being in biunivocal correspondence with the shades of grey, c) the electrode thus engraved is disposed (7) in a bench for machining by electro-erosion until a tool (8) having the desired surface state is obtained.
IPC 1-7
IPC 8 full level
B23H 9/06 (2006.01); B41C 1/04 (2006.01); B41M 3/10 (2006.01)
CPC (source: EP)
Designated contracting state (EPC)
AT BE CH DE ES FR GB GR IT LI LU NL SE
DOCDB simple family (publication)
EP 0252842 A1 19880113; EP 0252842 B1 19900411; AT E51785 T1 19900415; DE 3762195 D1 19900517; ES 2015072 B3 19900801; FR 2601271 A1 19880115; FR 2601271 B1 19900713; GR 3000445 T3 19910628
DOCDB simple family (application)
EP 87401604 A 19870708; AT 87401604 T 19870708; DE 3762195 T 19870708; ES 87401604 T 19870708; FR 8610089 A 19860710; GR 900400241 T 19900423